This disclosure generally relates to protective headgear and more particularly to a helmet with a flexible structure incorporated into the outer layer.
Conventional helmets include two primary components—a rigid outer layer and a compressible inner layer—that perform two non-overlapping functions. The rigid outer layer is made of an inflexible material and covers a user's head. The compressible inner layer is made of a softer material, typically a type of padding or foam, and is positioned between the rigid outer layer and the user's head. When a helmet with this structure is subjected to an impact, the rigid outer layer disperses the force of the impact over a broader area. However, because the outer layer is made of an inflexible material, the outer layer does not flex or deform in any significant manner when subjected to an impact. As a result, the rigid outer layer transfers nearly the entire force of the impact to the compressible inner layer, and the compressible inner layer is the only component of the helmet that attenuates the force of the impact. A helmet's rigid outer layer typically has the minimum thickness needed to provide rigidity for the purpose of dispersing the anticipated impact forces of the activity for which the helmet is designed. The thickness of a helmet's compressible inner layer is typically limited by broader design goals like reducing the overall size and weight of the helmet, and this leads to limited attenuation of the impact force relative to what would cause a mild traumatic brain injury (e.g., a concussion).
This limitation is compounded by helmets for certain sports, such as hockey and lacrosse, which typically have a rigid outer layer with ridges and bumps that protrude outward from the user's head. These ridges and bumps act as I-beams that add additional rigidity to the outer layer, which can decrease the effectiveness of the portion of the compressible inner layer positioned directly below the ridges and bumps. Specifically, the ridges and bumps direct impact forces through these I-beams, bypassing the attenuation material in the cavity of these protrusions, which in turn further limits the attenuation of the impact force by the helmet.